The spread spectrum communication is characterized in that emission spectrum spread of information to be transmitted is effected by using PN codes (e.g. M-code having a code length of 127) having a speed, which is much higher than the speed thereof, (with an enlarged frequency band), and on the receiver side the information is decoded by correlating a received signal with PN codes provided with in the receiver, and has features that deterioration of received signals due to frequency selective fading is reduced, etc.
As a spread spectrum receiver used for such a communication, there is known that disclosed in e.g. JP-A-59-18644-0. As illustrated in FIG. 4, the basic construction of this receiver consists of matched filters 1 and 2, a phase shifter 3 and a phase detector 4. The received signal S having a spread spectrum is inputted to the matched filter 1 and 2 and correlated there so that output signals A and B are obtained. Then the output signal B is shifted in phase by 90.degree. by the phase shifter 3. Finally, the output signal B shifted in phase and the output signal A stated above are given to the phase detector 4 to decode a data signal D.